JP3289375B2 - VEHICLE VEHICLE VEHICLE ESTIMATION DEVICE AND TIRE CONDITION DETECTOR USING ESTIMATED VEHICLE VEHICLE VEHICLE - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute speed estimating apparatus for estimating an absolute speed of a vehicle body and detecting a tire condition such as a tire pressure, a type of a tire, and a worn state of the tire by using the estimated absolute vehicle speed. The present invention relates to a tire condition detecting device that performs the following.

[0002]

2. Description of the Related Art Conventionally, various devices have been proposed for detecting a tire pressure as one of the tire states. One of them is to use the fact that the tire radius changes (shortens) when the tire air pressure decreases, and based on the detection signal of a wheel speed sensor that detects the wheel speed of each wheel, the air pressure of the vehicle tires is reduced. Some are indirectly detected.

In the above-mentioned conventional apparatus, when the wheel speed of one wheel becomes higher than the wheel speed of the other wheel, the tire radius of the wheel becomes lower than that of the other wheel due to the decrease in the tire air pressure of the one wheel. Assuming that the tire pressure has become shorter, a decrease in tire air pressure is detected.

[0004]

However, in the above-mentioned conventional apparatus, a change in tire radius of each wheel and a decrease in tire air pressure are detected from a relative comparison of wheel speeds of each wheel, so that sufficient detection accuracy is ensured. There is a problem that you can not.

That is, when the tire air pressure of only one wheel decreases, the above-mentioned conventional device can detect the decrease of the air pressure. For example, when the tire air pressure of all the wheels gradually decreases, etc. , It is impossible to detect this.

[0006] In addition, when the studless tire and the normal tire are combined and mounted on a vehicle, or when only one wheel is mounted on a tempered tire, the above-described conventional device causes a problem.

[0007] The present invention has been made in view of the above points, and when detecting a tire state such as tire pressure,
In order to detect the tire condition of each wheel with high accuracy, attention was paid to the absolute speed of the vehicle body. Therefore, it is a first object of the present invention to provide an absolute speed estimating device capable of accurately estimating the absolute speed of a vehicle body with a simple configuration.

Further, using the estimated absolute vehicle speed,
It is a second object of the present invention to provide a tire condition detecting device capable of detecting a tire condition such as a tire pressure, a tire type, and a tire wear condition with high accuracy.

[0009]

In order to achieve the first object, an absolute speed estimating apparatus according to the present invention is provided corresponding to a front wheel and a rear wheel of a vehicle. First and second output means for outputting a signal including a lower vibration frequency component, and an unsprung vibration frequency component of a front wheel and a rear wheel of the vehicle based on a signal output from the first and second output means. Detecting means for detecting the phase difference between the signals output by the first and second output means from the cross-correlation of the vehicle body, based on the phase difference detected by the detecting means and the length of the wheel base of the vehicle body, And an absolute speed estimating means for estimating the absolute speed.

In order to achieve the second object,
Tire condition detection devices according to the present invention are provided corresponding to the front wheels and rear wheels of the vehicle, and when the vehicle is running, first and second output means for outputting a signal including an unsprung vibration frequency component of the vehicle, The phase difference between the signals output by the first and second output means based on the cross-correlation of the unsprung vibration frequency components of the front and rear wheels of the vehicle based on the signals output by the first and second output means. Detecting means for detecting the vehicle speed, absolute speed estimating means for estimating the absolute speed of the vehicle body based on the phase difference detected by the detecting means and the length of the wheel base of the vehicle body, and wheel speed signals of the front wheels and rear wheels of the vehicle. A wheel speed signal output means for outputting a wheel radius signal from the magnitude of the wheel speed indicated by the wheel speed signal output from the wheel speed output means with respect to the absolute speed of the vehicle body estimated by the absolute speed estimation means. First to detect the tire state occurs
And a detecting means.

In the second object, in order to detect a type of a tire mounted on a vehicle as a tire state,
The tire condition detecting device according to the present invention is provided corresponding to the front wheel and the rear wheel of the vehicle, and outputs first and second output means for outputting a signal including an unsprung vibration frequency component of the vehicle when the vehicle is running. Based on the signals output by the first and second output means, the position between the signals output by the first and second output means is determined from the cross-correlation of the unsprung vibration frequency components of the front and rear wheels of the vehicle. Detecting means for detecting a phase difference; absolute speed estimating means for estimating an absolute speed of the vehicle body based on the phase difference detected by the detecting means and a length of a wheel base of the vehicle body; and wheel speeds of front and rear wheels of the vehicle A wheel speed signal output means for outputting a signal; and a wheel rotation signal indicated by the wheel speed signal output by the wheel speed output means, based on the absolute speed of the vehicle body estimated by the absolute speed estimation means. Calculating means for calculating a dynamic load radius which is a radius; extracting means for extracting a resonance frequency component signal of a vehicle unsprung from signals output by the first and second output means; From storage means for storing the relationship between the dynamic load radius of the tire and the unsprung resonance frequency, from the dynamic load radius of the tire calculated by the calculation means and the unsprung resonance frequency component signal extracted by the extraction means, Based on the relationship between the dynamic load radius of the tire and the unsprung resonance frequency stored in the storage means,
Determining means for determining the type of tire mounted on the vehicle.

In the second object, the tire condition detecting device according to the present invention is provided corresponding to the front wheel and the rear wheel of the vehicle to detect a tire wear condition as a tire condition. First and second output means for outputting a signal including an unsprung vibration frequency component of the vehicle;
Based on the signals output by the first and second output means,
Detecting means for detecting a phase difference between signals output by the first and second output means from a cross-correlation of unsprung vibration frequency components of a front wheel and a rear wheel of the vehicle; and a phase difference detected by the detecting means. An absolute speed estimating means for estimating an absolute speed of the vehicle body, a wheel speed signal output means for outputting wheel speed signals of front and rear wheels of the vehicle, and the absolute speed estimating means. From the estimated absolute speed of the vehicle body and the wheel speed indicated by the wheel speed signal output by the wheel speed output unit, calculating means for calculating a dynamic load radius that is a radius of rotation of the tire when the vehicle is traveling,
Extracting means for extracting a unsprung resonance frequency component signal of a vehicle from signals output by the first and second output means;
Storage means for storing the relationship between the dynamic load radius of the tire and the unsprung resonance frequency when the amount of tire wear is a predetermined value; and extraction of the dynamic load radius of the tire calculated by the calculation means and the extraction means Determining a wear state of the tire based on a relationship between a dynamic load radius of the tire and a resonance frequency of the unsprung stored in the storage means. It is characterized by having.

[0013]

According to the absolute vehicle speed estimating device having the above structure, the unsprung vibration of the front wheels and the rear wheels of the vehicle is based on the signal including the unsprung vibration frequency component of the vehicle output from the first and second output means. The phase difference between the signals output by the first and second output means is detected from the cross-correlation of the frequency components. Based on the phase difference and the known length of the wheelbase of the vehicle body, the absolute speed of the vehicle body is estimated.

Further, according to the tire condition detecting device having the above structure, the wheel speed signal output means outputs the wheel speed signals of the front wheels and the rear wheels of the vehicle. Then, the magnitude of the wheel speed indicated by the wheel speed signal with respect to the estimated absolute speed of the vehicle body is obtained. This makes it possible to individually compare the wheel speed of each wheel with respect to the absolute speed of the vehicle body, instead of the relative comparison of the wheel speed of each wheel. Based on this detection result, the tire condition in which the tire radius varies for each wheel is detected, so that even when the tire radius of a plurality of wheels is similarly short, it can be detected.

In the tire condition detecting device for detecting the type of tire mounted on the vehicle as the tire condition, a signal output from the first and second output means is used to calculate a resonance frequency component signal below the vehicle unsprung. And storage means for storing the relationship between the dynamic load radius of the tire and the unsprung resonance frequency for a plurality of types of tires. The unsprung resonance frequency fluctuates according to the tire air pressure. By extracting the unsprung resonance frequency, the tire air pressure can be predicted. On the other hand, since the dynamic load radius of the tire also varies depending on the air pressure of the tire, there is a fixed relationship between the unsprung resonance frequency and the dynamic load radius of the tire. Since this relationship changes depending on the type of tire, if the relationship between the calculated dynamic load radius of the tire and the extracted unsprung resonance frequency component signal is selected from the relationship stored in the storage means, The type of the tire mounted on the vehicle can be detected.

[0016] Further, in the tire condition detecting device for detecting the condition of tire wear as a tire condition, the relationship between the dynamic load radius of the tire and the resonance frequency of the unsprung portion when the amount of tire wear is a predetermined value is stored. Storage means. As described above, there is a fixed relationship between the unsprung resonance frequency and the dynamic load radius of the tire. However, when the tire wears and the tire radius changes, the relationship also changes. Therefore, the relationship between the dynamic load radius of the tire and the unsprung resonance frequency when the tire wear amount is a predetermined value is stored in advance, and the variation between the relationship and the calculated and extracted value is calculated. The state of wear of the tire can be detected from the variation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An absolute vehicle body estimating apparatus according to a first embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing the entire configuration of the first embodiment. As shown in FIG.
A wheel speed sensor is provided corresponding to 1d. Each wheel speed sensor includes gears 2a to 2d and pickup coils 3a to 3d. Gears 2a to 2d
Are coaxially mounted on the rotating shafts (not shown) of the tires 1a to 1d and are made of a disk-shaped magnetic material. The pickup coils 3a to 3d are connected to these gears 2a to 2d
Are mounted at predetermined intervals in the vicinity of the gears 2a to 2a.
2d, that is, an AC signal having a cycle corresponding to the rotation speed of the tires 1a to 1d is output. Pickup coil 3
AC signals output from a to 3d are output from a waveform shaping circuit R
Well-known electronic control unit (ECU) consisting of OM, RAM, etc.
4 to perform predetermined signal processing including waveform shaping. The result of the signal processing is input to the display unit 5, and the display unit 5 notifies the driver of the air pressure state of each of the tires 1a to 1d, the type of the tire, and the tire wear state.

The display unit 5 may independently display the tire condition (air pressure, type, wear) of each of the tires 1a to 1d, or may share one display surface with each of the tires 1a to 1d. The state of one tire may be displayed.

Here, the principle of calculating the absolute vehicle speed by calculating the phase delay from the cross-correlation in this embodiment will be described with reference to FIG. When the vehicle travels on, for example, a paved asphalt road surface, the tire receives vertical and longitudinal forces due to minute irregularities on the road surface, and the tire vibrates in the vertical and longitudinal directions. The frequency characteristic of the acceleration under the vehicle spring during the tire vibration is as shown in FIG. As shown in FIG. 3, the frequency characteristic of the acceleration shows a peak value at two points, a point a is a vertical resonance frequency under the spring of the vehicle, and a point b is a resonance frequency in the front-rear direction under the spring of the vehicle. is there.

On the other hand, as a result of detailed studies by the inventors, it has been found that the detection signal of the wheel speed sensor includes the frequency component of the unsprung acceleration, as shown in FIG. The peak value is shown at two points. Therefore, as shown in FIG. 2A, when the vehicle travels on a road surface at a certain vehicle speed VAB,
Front wheel speed signal F (t) and rear wheel speed signal R
(T) includes a vibration frequency component of the tire due to road surface input (irregularity).

For example, joint projections and manholes in a viaduct on an expressway, bumps and projections in a manhole, and a seam in a repaired portion of an asphalt pavement and a paint step in a pedestrian crossing are particularly noticeable.

In general, when the vehicle is running straight, the rear wheels are considered to run on almost the same road surface shape as the front wheels, so that the phase lag between the front and rear wheels does not depend on the road surface shape or tire wear. Is τ, the relationship of R (t) = F (t−τ) is established. (FIG. 2 (B)) Therefore, using the vehicle wheelbase L which is a known value, the absolute vehicle VAB is expressed by the following equation (1).

[0024]

VAB = L / τ Therefore, if the phase delay τ is obtained from the front and rear wheel speed signals F (t) and R (t), the absolute vehicle speed VAB can be estimated. In the calculation of the phase delay τ, for example, after the Fourier transform of the wheel speed signals F (t) and R (t) of the front and rear wheels, R (t) and F (t−τ) shown in the following Expression 2 are obtained.
From the cross-correlation R _{FR of}

[0025]

R _FR (t, t−τ) = E [R (t) · F (t−τ)] (where E []: total average) As a result, according to this embodiment, Vehicles equipped with an increasing number of anti-skid control devices (ABS) are already equipped with wheel speed sensors for each tire, so the absolute vehicle speed can be detected without adding any new sensors. It becomes possible.

Further, in the practical range of the vehicle, there is almost no influence on the wear and the type of the tire and the road surface condition. Further, since the vehicle wheel base L can be managed and measured in units of mm, the vehicle speed estimating apparatus can calculate the absolute vehicle speed with extremely high accuracy.

FIG. 5 is a flowchart showing the processing executed by the ECU 4. Note that the ECU 4 controls each wheel 1
In order to perform the same processing for a to 1d, the flowchart of FIG. 5 shows only the flow of processing for one of the front and rear wheels. In addition, in the following description, the suffix of each code is omitted.

In FIG. 5, in step 100, the AC signal (FIG.
After (B)) is shaped into a pulse signal, the wheel speed v is calculated by dividing the pulse interval by the time period. The wheel speed v generally includes many high-frequency components including a tire vibration frequency component. In step 110, it is determined whether the variation width Δv of the computed wheel speed v exceeds the reference value v _0. At this time, if it is determined that the fluctuation width Δv of the wheel speed v exceeds the reference value V ₀ , the process proceeds to step 120. In step 120,
It is determined whether or not the time ΔT during which the fluctuation width Δv of the wheel speed v exceeds the reference value v ₀ exceeds a predetermined time t ₀ . The processing in steps 110 and 120 is for determining whether or not the road surface on which the vehicle is traveling is a road surface on which the absolute vehicle speed can be detected by the detection method of the present embodiment. That is, in the present embodiment, the calculation of the vehicle body absolute vehicle speed is performed based on the signal included in the moving frequency component of the tire, so that the wheel speed needs to fluctuate to some extent.

In the determination in step 120,
The fluctuation width Δv of the wheel speed v is the reference value v ₀At the point when
A fixed time Δt is set, and the wheel
The variation width Δv of the speed v is equal to the reference value V₀Exceeds the time ΔT
Measurement is continued.

In steps 110 and 120, if both are affirmatively determined, the routine proceeds to step 130, and if either one is negatively determined, step 100 is performed.
Return to In step 130, a frequency analysis (for example, fast Fourier transform (FFT)) is performed on the calculated wheel speed.
Perform the operation.

Next, in steps 140 and 150, the cross-correlation function R _FR (τ) is obtained by inverse Fourier transform, and in step 150, the phase delay τ is calculated. Next, step 1
In step 70, the absolute vehicle speed V _AB of the vehicle body is obtained by the equation 1, and output in step 180.

The frequency range of the signal used in the fast Fourier transform (FFT) in step 130 does not need to use a signal that includes both unsprung up and down and front and rear directions as shown in FIG. As shown, after step 120, a region containing a large amount of unsprung vertical resonance frequency components (FIG. 4) through appropriate narrow band filters (B, P, F).
A), at least one of the regions (B in FIG. 4) in which a large number of unsprung front-back resonance frequency components are included, or both may be switched and used.

Based on the phase difference τ between the front and rear wheels, the absolute vehicle speed V _AB
As shown in FIG. 5, it is necessary to use the fast Fourier transform (for example, FFT) in order to obtain the following equation. However, this operation requires a large amount of memory (RAM) and the number of operations is large. The computational load may be a problem. In such a case, simple means is required, and the description will be made below.

FIG. 7 shows joints and concrete joints on a highway, manhole roads, and road joints, projections, and the like that are often seen in a renovation section of an asphalt road.
The following shows a typical pattern of vibration generated under a spring when a vehicle passes through a step or the like. This can be detected by the system configuration shown in FIG. 1 because it also appears in the wheel speed signal of the ABS.

Assuming that the vehicle travels almost straight ahead, the phase difference τ between the front and rear wheels can be detected by comparing characteristic waveforms in the time waveform. The processing flow of the ECU 4 will be described with reference to FIG. Since the same processing is performed for the front and rear wheels, only the processing for the front wheels will be described. In FIG. 8, steps 151 to 158 relate to the front wheels.
Steps 158, 161 to 167 relate to the rear wheels. In step 151, the wheel speed V calculated in step 100 is loaded into the RAM of the ECU 4 for the sampling time. In step 152, a magnitude comparison is performed with respect to a preset wheel speed fluctuation width ΔVt. This is because a relatively large input is obtained after passing through joint joints or the like, so that data is first selected based on the size of the input.

Next, in step 153, a peak search is performed to obtain V _Fmax . In step 154, a wheel speed fluctuation average value _VaVE in a time region other than the predetermined time width Ts is calculated around the V _Fmax obtained in step 153. In step 155, it obtains the ratio Kp of V _Fmax and V _AVE obtained, performs comparison between a preset value C at step 156. If an affirmative determination is made at this time, the time _TF at the time of occurrence of _VFmax is stored in step 157.

The above processing is for selecting a single-shot input from the wheel speed data in order to easily calculate the phase difference in the time domain. Here, from the front and rear wheels, T _F, T _R
Is calculated, the phase difference τ can be obtained from this difference. After obtaining the phase difference τ, the processing after step 170 in FIG. 5 is performed.

The above-described processing for obtaining the phase difference τ from the vibration components of the wheel speeds of the front and rear wheels is based on the premise that the front and rear wheels of the vehicle are traveling straight. Therefore, when the condition indicating the straight traveling state is satisfied, such as the condition that the wheel speed difference between the left and right wheels is equal to or less than a predetermined value, or the condition that the steering angle is equal to or less than a predetermined value by providing a separate steering sensor, To do.

In the above-described embodiment, the absolute speed of the vehicle body and the like are obtained from the vibration components of the wheel speeds of the front and rear wheels of the vehicle. However, the absolute speed and the like can be obtained from the wheel angular displacement, angular speed and angular acceleration. Next, a second embodiment of the present invention will be described. In the second embodiment, the dynamic load radius, which is the radius of rotation of the tire when the vehicle is running, is calculated by using the vehicle body absolute vehicle speed V _AB calculated above, and the tire pressure is detected based on the dynamic load radius. Is what you do. For this reason, in the second embodiment,
As shown in FIG. 9, the characteristic indicating the correspondence between the tire pressure and the tire dynamic load radius is stored as a map, and the tire pressure is directly estimated from the dynamic load radius calculated from the vehicle body absolute vehicle speed V _AB .

The radius of the tire dynamic load during running of the vehicle is affected by not only the tire pressure but also the load applied to the tire, the wear of the tire, and the vehicle speed. Therefore, in the map of the tire dynamic load radius and the air pressure shown in FIG.
Consider the variation due to wear and consider the width of variation. FIG. 10 is a map for obtaining the correction coefficient Kr of the tire dynamic load radius from the vehicle speed in consideration of the influence of the vehicle speed.

In the second embodiment, only the processing contents in the ECU 4 are different from those in the first embodiment, and the configuration is the same. Therefore, the description of the configuration is omitted, and only the processing contents are described.
The processing content of the second embodiment will be described with reference to the flowchart of FIG. Steps 200 to 220 have the same contents as the arithmetic processing of steps 100 to 130 in the flowchart (FIG. 5) of the first embodiment, and a description thereof will be omitted.

After the FFT processing in step 220, the number of FFT calculations is counted in step 225, and it is determined in step 230 whether the number of calculations N has reached a predetermined value No.
If an affirmative determination is made in step 230, an average process of the FFT calculation results is performed a predetermined number of times in step 235, and in steps 240 and 245, a cross-correlation R _FR (τ) between the front and rear wheels is obtained by inverse Fourier transform. In step 250, a phase difference τ between the front and rear wheels is obtained from the cross-correlation R _FR (τ). Note that the processing of Steps 225 to 230 is for eliminating the influence of noise, and may be omitted depending on the road surface condition and the vehicle speed.

Next, at step 255, the vehicle absolute base vehicle speed V is obtained by dividing the vehicle wheel base L by the phase difference τ.
_AB is required. In step 260, the tire dynamic load radius r _AB is calculated from the number of pulses (n) counted within a predetermined time (dt) in proportion to the rotational speed of the wheels and the calculated vehicle absolute vehicle speed V _AB . Step 26
5 is a correction coefficient K of the tire dynamic load radius with respect to the vehicle speed V _AB .
_V is obtained from the map, and the corrected tire dynamic load radius r _RF is obtained.

In step 270, the tire pressure P is calculated from the relationship between the corrected tire dynamic load radius and the tire pressure (FIG. 9).
r is estimated. Then, in step 275, the calculated tire pressure P is compared with a preset allowable lower limit value P ₀ of the tire pressure, and when the calculated tire pressure P is equal to or less than the allowable lower limit value P ₀ , the process proceeds to step 280. move on.

In step 280, a warning is displayed on the display unit 5 indicating that the tire air pressure has dropped. Next, a third embodiment of the present invention will be described with reference to the flowchart of FIG.

FIGS. 3 and 4 show that the unsprung resonance frequency can be detected from the wheel speed signal of each wheel. However, when the tire air pressure decreases, the unsprung resonance frequency becomes as shown in FIG. As shown, the resonance points in the unsprung vertical and longitudinal directions both decrease. For this reason, the state of the tire pressure can be detected by detecting at least one of the resonance point changes.

In the third embodiment, the resonance point below the spring is
The tire pressure condition is detected from the change and
From the dynamic load radius of the tire described in the second embodiment,
Detects the air pressure condition of the ear. And each detected
When the deviation between the tire pressures Pf and Pr is equal to or less than a predetermined value ΔP.
And Pf and Pr are the allowable lower limit values P of the tire pressure. ₀
Is configured to issue a warning when the value falls below
is there.

In the flow charts of FIGS. 14 and 15, steps 300 to 370 are the same as steps 200 to 270 of the second embodiment, and therefore description thereof is omitted. In step 375, in the averaging process performed in step 335, a moving average process is performed in order to make it easier to see the resonance point in consideration of a case where averaging is not sufficient. Step 3
In 80 detects at least one of the resonance point f _K in the vertical direction or the longitudinal direction of the unsprung. In step 385, FIG.
As shown in FIG. 3, the relationship between the resonance point and the tire pressure (FIG. 1)
From 3), the current tire pressure Pf is estimated.

On the basis of the tire pressures Pr and Pf estimated in steps 370 and 385, step 390 calculates a deviation between the two, and only when this deviation is equal to or smaller than a predetermined value ΔP, the routine proceeds to step 395. If both values in step 395 are both equal to or less than the allowable lower limit value P ₀ of the tire pressure only, displays a warning at step 396. According to such a configuration, detection of the tire air pressure becomes more accurate, and erroneous determination can be prevented.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The processing of the electronic control unit according to the fourth embodiment is shown in the flowcharts of FIGS. 16 and 17, but steps 400 to 430 in FIG.
The description is omitted because it is the same as the embodiment.

In step 435, the running vehicle speed V _{X of the} vehicle
There a judgment of whether or not present in the range of the upper limit speed V _H from a predetermined lower limit vehicle speed V _L, step 4 if an affirmative determination
Proceed to 40. Here, the lower limit vehicle speed _VL and the upper limit vehicle speed _VH are
It is desirable to set the values to about 10 km / h and 150 km / h, respectively. In step 440, the variation width Δv of the wheel speed V calculated in step 400 is compared with a predetermined value v _L. Note that the determination reference value v _{L at} step 440 is
Needless to say, it is set higher than the criterion value v _{O of} 5.

Here, when the tire air pressure is estimated and calculated from the unsprung resonance frequency f _K , the detection principle is based on the magnitude of the vibration component in a specific frequency region in the unsprung vibration, In this case, since the vibration itself hardly occurs, there is a problem that the accuracy of the required tire air pressure is apt to be reduced. In addition, even when the vehicle is running at high speed (for example, 150 km / h or more), unsprung vibration is less likely to occur, and tire air pressure is difficult to detect. Further, when the vehicle is traveling on ice, for example, the traveling road surface is smooth and the vibration is small, and the detection accuracy is also lowered.

Therefore, according to steps 435 and 440,
The vehicle speed is out of the constant vehicle speed range (V_L≤V _X≤V_H) And
Air pressure detection on good roads with few road inputs
Body speed V_ABTire dynamic load radius r calculated from_ABFor
And performs air pressure detection.

The processing in steps 485 to 495 is performed under unsprung
For detecting tire pressure from the resonance frequency
The description is omitted because it is the same as the third embodiment.
On the other hand, if a negative determination is made in step 435 or 440,
Proceeds to step 445, but proceeds to steps 445-480.
Is to detect the tire pressure from the dynamic load radius of the tire.
This is the same as in the third embodiment, and will not be described. What
In step 470, the value obtained from the phase difference τ between the front and rear wheels is
The difference between the left and right absolute vehicle speeds is a predetermined value ΔV _ABBelow (straight
After confirming that the state is, the process proceeds to step 475. S
In step 496, step 480 or step 49 is performed.
Preset with pressure Pf or Pr estimated and calculated in 5
Allowable lower limit value P of tire pressure_OCompare with and calculate
Tire pressure Pf or Pr is the allowable lower limit P_OLess than
If so, the process proceeds to step 497 to display a warning.

Next, a fifth embodiment of the present invention will be described. Third previously mentioned, at the detection of the tire pressure by the unsprung resonance frequency f _K mentioned fourth embodiment, but is excellent in that it can be made reliably air pressure determination, considering tires Therefore, the reference value f _L for determining the allowable limit air pressure is a constant value, and there is a problem in that accurate determination cannot be made when the tire is replaced. Therefore, in the fifth embodiment, the state of the tire air pressure can be accurately detected even when the tire is replaced.

In the practical range of the vehicle, the change in the resonance frequency is mostly due to the change in the tire spring constant caused by the change in the tire air pressure, so that it is unaffected by other factors such as tire wear. Air pressure detection is possible. Therefore, if the change in the unsprung resonance frequency in either the up-down direction or the front-back direction is detected, the tire air pressure can be accurately detected. However,
This is based on the same kind of tire, and FIG.
As shown in the above, even if the unsprung resonance frequency is the same, the tire air pressure differs depending on the type of tire, and the reference value (unsprung resonance frequency) for judging an abnormal air pressure also differs. Therefore, the case where the determination value is affected by tire replacement is broadly divided into three cases. That is, line x in the figure is a normal radial tire, line y is a studless tire, line z
Indicates a flat tire, and the criterion values fLa, fLb, fLc corresponding to the tire type are stored in the electronic control unit 4 in advance.

The determination of the tire type is performed using the dynamic load radius of the tire and the unsprung resonance frequency. That is, FIG.
As shown in, unsprung resonance frequency f _K at that time the tire rolling radius V _RF is almost one-to-one correspondence with the type of tire (x in the figure, y, z corresponds to the tire type described above ), The type of the tire can be determined from both values. Therefore, as a tire replacement determination map, FIG.
9 is stored in the electronic control unit 4. Electronic control device 4 that detects air pressure and issues a warning based on the above description
Will be described with reference to the flowcharts of FIGS. 20 and 21. Since the electronic control unit 4 performs the same processing for each of the wheels 1a to 1d, the flowchart shows only the flow of the processing for one wheel. Further, this flowchart shows an example in which it is detected that the air pressure of the tire has dropped below the reference value, and a warning is issued to the driver.

The processing of steps 501 to 535 is the same as the processing of the above-described embodiment, and therefore the description is omitted. The processing in step 515 is for determining whether or not the tire type has already been determined.
If = 1, it is determined that the determination has already been made, and the routine proceeds to step 550.

In steps 540 to 542, step 5
An inverse Fourier transform is performed on the average processing result of the FFT obtained in step 35, and a phase difference τ is obtained from the cross-correlation function R _FR (τ) of the front and rear wheels. In step 543, the phase difference τ and the wheel base L are obtained. Obtain the absolute vehicle speed V _AB . next,
In step 544, it calculates the tire rolling radius r _AB from the pulse number n in V _AB and the predetermined time dT.

On the other hand, in step 545, further averaging processing is performed on the result of Fourier transform (FFT) in parallel with the processing in steps 540 to 544, and in step 546, the unsprung resonance frequency f _S is extracted.

In step 547, the tire type is determined based on the map shown in FIG. 19 based on the tire load radius r _AB obtained in step 544 and the unsprung resonance frequency f _S obtained in step 546. In the following step 548, the reference values fLa, fLb, fLc of the unsprung resonance frequency corresponding to the determined tire type are selected based on the above-mentioned 18 maps, and stored as the alarm required reference value fL.

Subsequently, at step 549, the flag F is set to "1". Thus, steps 520 to 549 for determining tire replacement are executed only immediately after the vehicle starts. Actually, the step 548 is performed by
This processing is executed only when it is determined in step 547 that all the wheels or two driving wheels are to be replaced.

Once it is determined that the tire is to be replaced, the process returns to step 501, and if a positive determination is made in each of steps 505, 510 and 515, the process proceeds to step 550.
In step 550, the wheel speed v obtained within the time ΔT is obtained.
Fast Fourier transform (FFT) performs a frequency analysis operation, counts the number of operations n, at step 555 until the operation number n of the frequency analysis becomes a predetermined number n _0, step 501 following repeated for It is. Averaging the calculated values of step 560 in the frequency analysis, further moving average processing a predetermined number of arithmetic average value of the past in step 565, it calculates the unsprung resonance frequency f _K, based on the result at step 570.

[0064] Thus, in step 575, step if the computed the resonance frequency f _K is sure becomes equal to or less than the alarm reference value fL, becomes equal to or less than the reference value fL 5
At 80, a warning is given that the tire pressure is too low.

The determination of the tire type in step 547 of FIG. 20 may be performed using a regional map as shown in FIG. 22 instead of the linear map shown in FIG. A normal radial tire, a studless tire, and a tire tire according to whether the value of the tire dynamic load determination V _AB and the unsprung resonance frequency f _S calculated in steps 544 and 546 belong to the X region, the Y region, and the Z region in FIG. Judge tires and flat tires. Also in this case, the alarm reference value is finally changed only when it is determined that tire replacement is to be performed for all four wheels or for two driving wheels, as in the first embodiment.

Further, the determination of the tire type can be performed by using the matrix shown in FIG. That is, nine types are obtained by increasing and decreasing the tire load radius r _AB and the unsprung resonance frequency f _S measured at the start of traveling based on the tire dynamic load radius r ₀ and the unsprung resonance frequency f ₀ of the normal radial tire at the time of factory shipment. Is determined by the following matrix.

For example, when a normal radial tire is mounted, the tire load radius decreases at the same time as the unsprung resonance frequency decreases due to a decrease in tire air pressure, and when the tire air pressure is supplied, the tire load radius increases with the unsprung resonance frequency. Increase. FIG. 2 shows this characteristic on a matrix.
3 is a part.

In the studless tire, since the rubber material used is soft, the unsprung resonance frequency is lowered as a whole, and becomes a portion shown by b in FIG. Also, in the case of a flat tire, since the tire spring constant is generally high due to the influence of the flattening rate, the unsprung resonance frequency becomes high as a whole.
C.

In this case, the hatched portion in FIG. 23 is a portion where it is difficult to determine whether the tire is a normal radial tire or another tire, but can be estimated by considering it together with the determination result for other wheels. . That is, it is rare that two or four wheels simultaneously decrease or increase the air pressure. In such a case, it is determined that the tire has been replaced. In this case, when the unsprung resonance frequency and the tire load radius of the four wheels or the two driving wheels are simultaneously reduced, it is determined that the tire is to be replaced with a studless tire, and conversely, when it is increased, it is determined that the tire is to be replaced with a flat tire.

As the reference values r _{0 and} f ₀ , values at the time of normal air pressure of a normal radial tire or values immediately before the vehicle stops can be used. Next, the sixth embodiment of the present invention
An example will be described. In the sixth embodiment, the wear state of the tire is detected based on the dynamic load radius of the tire and the unsprung resonance frequency component.

As described above, the unsprung resonance frequency component is extracted from the detection signal of the wheel speed sensor for detecting the wheel speed of each wheel, and the tire pressure can be calculated from the resonance frequency component. Are not affected by wear. For this reason, the relationship between the tire dynamic load radius and the resonance frequency in the straight running state of the vehicle and in the normal state is determined, and the tire wear amount and abnormal wear are determined based on the deviation of the tire dynamic load radius from this reference value. Can be detected.

Here, the tire dynamic load radius r _AB calculated from the absolute vehicle speed V _AB calculated based on the first embodiment.
FIG. 24 shows the relationship between (m) and the tire pressure (kg / cm ² ). FIG. 25 shows the relationship between the unsprung resonance frequency f _K (HZ) calculated based on the third embodiment and the tire air pressure (kg / cm ² ). From FIG. 24 and FIG. 25, FIG. 26 shows the relationship between the tire dynamic load radius r _AB and the unsprung resonance frequency f _K. The relationship shown in FIG. 26 shows a characteristic in a case where the tire dynamic load radius changes only due to a change in the tire air pressure in a state where the tire does not wear, and the vehicle travels linearly for a certain unit time (constant time). The case is assumed. When the four wheels are not in the worn state or when the four wheels are in the same worn state, the relationship between the tire resonance frequency (tire pressure) of each wheel and the tire dynamic load radius is represented by a point P in FIG. ₁ has a certain correlation as shown in to P _4, it is plotted on a particular line.

The point P ₁ indicates the case where the tire pressure is the lowest, and the point P ₄ indicates the case where the tire pressure is the highest.
FIG. 27 shows that the tire pressure is Pi and the tire resonance frequency is f.
Although the tire calculated as i is taken as an example, it shows the fi-Pi characteristic when there is no wear. Pi _L is
Pi _H indicates a case where the air pressure is reduced, and Pi _H indicates a case where the air is supplied too much. On the other hand, although the air pressure is Pi, in the case of a worn tire, the tire dynamic load radius becomes the _RRFi point. That is, by calculating Δr in the figure, the amount of tire wear can be detected.

To actually do this, the relationship between the tire air pressure and the tire resonance frequency shown in FIG. 27 is stored as a map, and the phase difference τ calculated from the wheel speed signals of the front and rear wheels is obtained. It is necessary to calculate the tire dynamic load radius r _AB obtained from _AB , further obtain the unsprung resonance frequency, and calculate the wear amount Δr from the relationship with the map. This makes it possible to compare with the predetermined wear amount r ₀ and to notify the driver of abnormal wear of the tire on the display 5. Based on the above theoretical idea, the signal processing of the ECU 4 for detecting that the amount of wear of the tire has reached the reference value or more and issuing a warning to the driver is shown in FIGS. 28 and 29.
This will be described with reference to the flowchart of FIG.

The ECU 4 independently performs the same processing for each of the wheels 1a to 1d. In the flowcharts shown in FIGS. 28 and 29, the processing for one wheel is shown, and the suffix of each code is omitted. Steps 600 to 637 and steps 640 to 650 are the same as those in the above-described embodiment, and thus description thereof is omitted.

At step 636, the corrected tire dynamic load radius r _RF is calculated from the correction coefficient K _V in consideration of the effect of the vehicle speed on the tire dynamic load radius r _AB in the running state obtained at step 635. Also from a map stored in advance at step 655 ECU 4 by the unsprung resonance frequency f _K obtained in step 650, the tire rolling radius R _RF in the absence of wear is determined. In step 660, the tire wear amount Δr is calculated from the respective dynamic load radii R _RF and r _RF obtained in steps 636 and 655, and in step 665, the magnitude is compared with a predetermined wear amount mH. At step 670, the driver is warned by the display 5.

Next, a seventh embodiment of the present invention will be described below. In the seventh embodiment, when estimating the tire air pressure based on the tire dynamic load radius, the tire wear amount is estimated based on the tire dynamic load radius and the unsprung resonance frequency, and the tire dynamic load radius is estimated based on the estimated tire wear amount. Correction and calculation are performed to accurately detect the tire air pressure.

The processing of the ECU 4 in this embodiment is shown in FIG.
0, shown in FIG. 31, where steps 700-714
FIG. 11 of the second embodiment (steps 200 to 265)
Therefore, detailed description is omitted. Step 700
In steps 706 to 706, after calculating the wheel speed V, determining the road surface condition and the road surface length, a Fourier transform (FFT) is performed, and a predetermined FFT is performed.
When the number of calculations is reached, the averaging process is performed. Next, in steps 710 to 713, an inverse Fourier transform is performed, a phase difference τ of the front and rear wheels is obtained from the cross-correlation function R _FR (τ), and the tire degree is calculated from the vehicle body absolute vehicle speed V _AB to obtain the load radius r _AB . Ask. Next, in step 714, taking into account the influence of tire rolling radius of the vehicle speed by the correction factor K _V, obtaining a corrected tire rolling radius R _RF. On the other hand, steps 720 to 72
In 2, with respect to the average processing result of step 706, further performs a moving average process, calculates the unsprung resonance frequency f _K by peak search. In step 722, as shown in FIG. 28 in the sixth embodiment, the tire rolling radius R _RF in the absence of wear is calculated from the relationship between the unsprung resonance frequency f _K and the tire rolling radius.

[0079] Check the step 730 the flag F process proceeds to "1" unless the step 735, the tire wear amount Δr is calculated from the R _RF and r _RF the calculated. Once the amount of wear is calculated during running, the flag F is set to "1" in step 736. This is because if the amount of wear of the tire is calculated once after the start, it is unlikely that it will increase during running, so it is considered that the calculation of the amount of wear after the start of the vehicle should be performed only once. is there. Further, it is not necessary to always calculate Δr (wear amount) after the start or after the IGON, and this processing may be performed once every several times.

[0080] At step 740, to calculate tire rolling radius at step 714, the wear amount Δr is corrected (this case is added), it is replaced with a new tire rolling radius r _FF. In step 745, the tire pressure Pr at that time is estimated from the relationship between the tire pressure and the corrected tire dynamic load radius, similarly to FIG. 9 shown in the second embodiment. In step 750, performs a comparison between the allowable limit value P ₀ of a preset tire pressure and the sensed tire pressure Pr, if an affirmative determination process proceeds to step 755, a warning is displayed by the display 5.

In the above-described embodiments, the detection of the tire air pressure, the type of the tire, the worn state of the tire, and the like has been described. It is very useful to provide information on the tires detected in these embodiments to a device that controls the running state of another vehicle. For example, an anti-lock brake (ABS) for preventing a locked state of wheels during braking
In, the reference value for reducing the brake pressure can be corrected according to the type of the wheel. Thus, the control can be started at an appropriate timing, so that the braking efficiency is improved.

In addition to the above-mentioned ABS, application to a TRC (traction control system), 4WS (four-wheel steering system), and the like is possible.

[0083]

As described above, according to the absolute vehicle speed estimating apparatus of the present invention, the phase difference is detected from the cross-correlation between the unsprung vibration frequency components of the front wheels and the rear wheels of the vehicle, and based on this phase difference, Since the absolute speed of the vehicle body is estimated, the absolute speed of the vehicle body can be accurately estimated with a simple configuration.

Further, according to the tire condition detecting device of the present invention, the tire condition in which the tire radius varies is detected by comparing the estimated absolute speed of the vehicle body with the wheel speed. It is possible to individually compare the wheel speed of each wheel with respect to the absolute speed of the vehicle body instead of the relative comparison of the speed. Therefore, even when the tire radii of a plurality of wheels are similarly shortened, it is possible to detect this, and the detection accuracy can be improved.

In the tire condition detecting device for detecting the type of the tire mounted on the vehicle as the tire condition, a resonance frequency component signal under the spring of the vehicle is extracted, and the dynamic load radius of the tire is determined for a plurality of types of tires. And the relationship between the unsprung resonance frequency and the unsprung resonance frequency, the type of the tire mounted on the vehicle is determined based on the relationship between the calculated dynamic load radius of the tire and the extracted unsprung resonance frequency component signal. It can be detected with high accuracy.

Further, in the tire condition detecting device for detecting the condition of tire wear as the tire condition, the relationship between the dynamic load radius of the tire and the resonance frequency of the unsprung state when the amount of tire wear is a predetermined value is stored. Since the amount of change from the relationship between the calculated and extracted values is determined, the tire wear state can be detected with high accuracy from the amount of change.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a principle of calculating a phase delay from a cross-correlation of vibration components of wheel speeds of front and rear wheels and calculating an absolute vehicle speed.

FIG. 3 is a characteristic diagram illustrating frequency characteristics of unsprung acceleration of a vehicle.

FIG. 4 is a characteristic diagram showing a frequency characteristic of a wheel speed.

FIG. 5 is a flowchart showing processing contents of the electronic control device of the first embodiment.

FIG. 6 is a flowchart for explaining a modification of the first embodiment.

FIG. 7 is an explanatory diagram for explaining the principle of another modification of the first embodiment.

FIG. 8 is a flowchart showing processing contents of an electronic control device according to another modification of the first embodiment.

FIG. 9 is a characteristic diagram showing a relationship between a corrected tire dynamic load radius and a tire pressure.

FIG. 10 is a characteristic diagram illustrating a relationship between a correction coefficient of a tire dynamic load radius and a vehicle speed.

FIG. 11 is a flowchart illustrating processing contents of an electronic control device according to a second embodiment.

FIG. 12 is a characteristic diagram illustrating a change in resonance frequency in a vertical direction and a longitudinal direction below a spring of a vehicle due to a change in tire air pressure.

FIG. 13 is a characteristic diagram showing a relationship between an unsprung resonance frequency of a vehicle and a tire air pressure.

FIG. 14 is a flowchart illustrating a part of the processing content of the electronic control device of the third embodiment.

FIG. 15 is a flowchart showing the remaining part of the processing content of the electronic control device of the third embodiment.

FIG. 16 is a flowchart showing a part of the processing content of the electronic control device of the fourth embodiment.

FIG. 17 is a flowchart showing the remaining part of the processing content of the electronic control device of the fourth embodiment.

FIG. 18 is a characteristic diagram showing the relationship between the unsprung resonance frequency and tire air pressure according to the type of tire.

FIG. 19 is a characteristic diagram showing the relationship between the unsprung resonance frequency of the vehicle and the tire dynamic load radius according to the type of tire.

FIG. 20 is a flowchart showing a part of the processing content of the electronic control device of the fifth embodiment.

FIG. 21 is a flowchart showing the remaining part of the processing content of the electronic control device of the fifth embodiment.

FIG. 22 is a characteristic diagram showing a relationship between the unsprung resonance frequency of the vehicle and the tire dynamic load radius.

FIG. 23 is a map showing the relationship between the unsprung resonance frequency of the vehicle and the tire dynamic load radius.

FIG. 24 is a characteristic diagram showing a relationship between a tire dynamic load radius and a tire air pressure.

FIG. 25 is a characteristic diagram showing a relationship between an unsprung resonance frequency of a vehicle and a tire air pressure.

FIG. 26 is a characteristic diagram showing the relationship between the unsprung resonance frequency of the vehicle and the tire dynamic load radius.

FIG. 27 is an explanatory diagram for explaining the principle of detecting a worn state of a tire.

FIG. 28 is a flowchart showing a part of the processing content of the electronic control device of the sixth embodiment.

FIG. 29 is a flowchart showing the remaining part of the processing content of the electronic control unit of the sixth embodiment.

FIG. 30 is a flowchart showing a part of the processing content of the electronic control device of the seventh embodiment.

FIG. 31 is a flowchart showing the remaining part of the processing content of the electronic control device of the seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tire 2 Gear 3 Pickup coil 4 Electronic control unit (ECU) 5 Display

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kenji Fujiwara 1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-1-295167 (JP, A) JP-A-62- 149502 (JP, A) JP-A-62-149503 (JP, A) JP-A-59-160605 (JP, A) JP-A-5-133831 (JP, A) "Automotive Technology Handbook"<firstvolume> Basics / Theory, The Society of Automotive Engineers of Japan, December 1, 1990 (58) Fields investigated (Int. Cl. ⁷ , DB name) B60C 23/00-23/08

Claims (10)

(57) [Claims] 1. First and second output means provided corresponding to a front wheel and a rear wheel of a vehicle and outputting a signal including a vibration frequency component below a spring of the vehicle when the vehicle travels, And the signal output by the second output means,
Detecting means for detecting a phase difference between signals output by the first and second output means from a cross-correlation of unsprung vibration frequency components of a front wheel and a rear wheel of the vehicle; and a phase difference detected by the detecting means. A vehicle speed estimating device comprising: an absolute speed estimating means for estimating an absolute speed of the vehicle body based on the length of the wheel base of the vehicle body. 2. First and second output means provided corresponding to a front wheel and a rear wheel of a vehicle and outputting a signal including a vibration frequency component under a spring of the vehicle when the vehicle travels, And the signal output by the second output means,
Detecting means for detecting a phase difference between signals output by the first and second output means from a cross-correlation of unsprung vibration frequency components of a front wheel and a rear wheel of the vehicle; and a phase difference detected by the detecting means. An absolute speed estimating means for estimating an absolute speed of the vehicle body, a wheel speed signal outputting means for outputting wheel speed signals of front wheels and rear wheels of the vehicle, and an absolute speed estimating means. First detection means for detecting a tire state in which a change in tire radius occurs from the magnitude of the wheel speed indicated by the wheel speed signal output from the wheel speed output means with respect to the estimated absolute speed of the vehicle body. Tire state detecting device. 3. The tire condition detecting device according to claim 2, wherein the wheel speed signal output means is used as the first and second output means, and the front and rear wheels of the vehicle output by the wheel speed signal output means. A tire condition detecting device, wherein a wheel speed signal of a wheel is used as a signal including a vibration frequency component of a vehicle unsprung. 4. The tire condition detecting device according to claim 2, wherein the tire condition in which the change in the tire radius detected by the first detecting means occurs is a change in the tire pressure. apparatus. 5. The tire condition detecting device according to claim 4, wherein the extraction means extracts a resonance frequency component signal of a vehicle unsprung from a signal output from the first and second output means, and the extraction means. A second detecting means for detecting a change in the tire air pressure from a change in the unsprung resonance frequency component signal extracted by the second detecting means; and a first detecting means and a second detecting means for detecting the change in the tire air pressure. And a determination means for determining that a change in tire air pressure has occurred when both of the detection means detect a similar change. 6. The tire condition detecting device according to claim 4, wherein said extracting means extracts a resonance frequency component signal of a vehicle unsprung from a signal output by said first and second output means. Detecting a change in tire air pressure from a change in the unsprung resonance frequency component signal extracted by the first detecting means; and detecting the change in tire air pressure according to a predetermined condition when detecting the change in tire air pressure. And a switching means for switching between the first detection means and the second detection means. 7. The tire condition detecting device according to claim 6, further comprising: a traveling road surface detecting unit that detects an uneven state of the traveling road surface of the vehicle; and a traveling state detecting unit that detects a traveling state of the vehicle. The switching means switches between the first detection means and the second detection means based on the detection results of the traveling road surface detection means and the traveling state detection means. 8. First and second output means provided corresponding to a front wheel and a rear wheel of the vehicle and outputting a signal including a vibration frequency component below a spring of the vehicle when the vehicle travels, And the signal output by the second output means,
Detecting means for detecting a phase difference between signals output by the first and second output means from a cross-correlation of unsprung vibration frequency components of a front wheel and a rear wheel of the vehicle; and a phase difference detected by the detecting means. An absolute speed estimating means for estimating an absolute speed of the vehicle body, a wheel speed signal outputting means for outputting wheel speed signals of front wheels and rear wheels of the vehicle, and an absolute speed estimating means. Calculating means for calculating a dynamic load radius which is a turning radius of a tire when the vehicle is running, from the estimated absolute speed of the vehicle body and a wheel speed indicated by a wheel speed signal output by the wheel speed output means; Extracting means for extracting an unsprung resonance frequency component signal of the vehicle from the signal output by the second output means; and a dynamic load radius of the tire and a resonance frequency of the unsprung resonance for a plurality of types of tires. Storage means for storing a relationship with the wave number, from the dynamic load radius of the tire calculated by the calculation means and the unsprung resonance frequency component signal extracted by the extraction means, of the tire stored in the storage means A tire condition detection device comprising: a determination unit configured to determine a type of a tire mounted on a vehicle based on a relationship between a dynamic load radius and a resonance frequency of the unsprung portion. 9. First and second output means provided corresponding to a front wheel and a rear wheel of a vehicle and outputting a signal including a vibration frequency component under a spring of the vehicle when the vehicle is running, the first and second output means, And the signal output by the second output means,
Detecting means for detecting a phase difference between signals output by the first and second output means from a cross-correlation of unsprung vibration frequency components of a front wheel and a rear wheel of the vehicle; and a phase difference detected by the detecting means. An absolute speed estimating means for estimating an absolute speed of the vehicle body, a wheel speed signal outputting means for outputting wheel speed signals of front wheels and rear wheels of the vehicle, and an absolute speed estimating means. Calculating means for calculating a dynamic load radius which is a turning radius of a tire when the vehicle is running, from the estimated absolute speed of the vehicle body and a wheel speed indicated by a wheel speed signal output by the wheel speed output means; Extracting means for extracting a resonance frequency component signal of a vehicle unsprung from a signal output by the second output means; a dynamic load radius of the tire when the amount of tire wear is a predetermined value; Storage means for storing the relationship between the resonance frequency of the tire, and the dynamic load radius of the tire calculated by the calculation means and the unsprung resonance frequency component signal extracted by the extraction means are stored in the storage means of the tire A tire condition detecting device comprising: a determination unit configured to determine a wear state of the tire based on a relationship between a dynamic load radius and a resonance frequency of the unsprung part. 10. The tire condition detecting device according to claim 9, wherein a detecting means for detecting a tire pressure based on a dynamic load radius of the tire, and wherein the determining means determines a tire pressure detected by the detecting means. And a correcting means for correcting according to the wear state of the tire.